In certain circuits conducting a pressurised fluid, safety valves are installed in order to limit the pressure of the fluid to a predetermined value. In a body provided with a cavity adapted to conduct the fluid between an inlet aperture and an outlet aperture, a safety valve contains a valve head cooperating with a seat for the purpose of opening or closing the cavity. The valve head is normally applied against the seat.
Use is made of calibrated valves in which the valve head is applied against the seat through the action of a calibrated spring. Use is also made of pilot-operated valves in which the movement of the valve head is controlled by a pilot device.
In certain circuits, such as the radioactive water circuits of nuclear reactors, it is desired to achieve great operating safety of safety valves.
Regular testing of the safety valves used is necessary, and for this purpose use is made of test benches. For example, FR No. 2.524.603 describes a test bench on which the valve is mounted and which comprises on the one hand a pushing means for displacing the valve head against the action of the calibrated spring, and on the other hand a valve head displacement transducer and a transducer measuring the force applied to the valve head, the signals supplied by these transducers being transmitted to a recorder. For different speeds it is thus possible to obtain curves indicating the response of the calibrated spring.